What happens when a fruit fly fails to reproduce?
none of its genes will pass into the next generation.
its genes must be carried by another individual in the population.
only some of its genes will pass into the next generation.
its genes will skip a generation.

None of its genes will pass onto the next generation. None of the other options are correct because it is impossible for the genes of an individual to be passed onto the next generation through another individual. It is impossible for "only some of its genes" to pass onto the next generation because as long as it fails to reproduce, NONE of its genes could possibly pass onto any supposed offspring. And it is impossible for its genes to skip a generation because that doesn't make any sense.
Hope that helped you.